Radio beacon course shifting method



Aug. 22, 1933. KEAR 1,923,934

RADIO smcon COURSE smmme METHOD Filed Nov. 24. 1951 s Sheets-Sheet 1 FIG.1.

Aug. 22, 1933. KEAR 1,923,934

RADIO BEACON COURSE SHIFTING METHOD Filed Nov. 24, 1931 3 Sheets-Sheet 2 Aug. 22, 1933. F'. G. KEAR RADIO BEACON COURSE SHIFTING METHOD Filed Nov.- 24, 1931 3 Sheets-Shea. 3

FIG. 5

WM a M Patented Aug. 22, 1933- r PATENT wFFiC RADIO enAooNeoUnsE SHIFTING METRO 'FrankG. Kear, Minersville, Pa., assignor to the Government of the United States Application November 24, 1931 h Serial No. 577,025 1 2 Claims. (CL' 250-11) (Granted under the Act at March 3, 1883, as 1 amended April so, 1928; 370 o. e. 757) 'The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes.without the payment to me of any royaltythereon. This invention relates generally, to radio beacons and has more particular reference to a novel method and apparatus for adjusting the direction of radio beacon courses.

It has long been appreciated that a limitation of the radio range-beacon its early form has I been the factthat the four coursesemanating from a'single radio range-beaconhave been at fixed angles of 90 to each other. ,It is obvious that such an arrangement could serve only one 15 course at'a time when situated at anairp ort except whereby rare coincidencetwoicourses extended at 90 or 180 from an airport. In order to make at least two of the four available courses useful the radio beacon installations could be situated halfway between points on the straight airways at distances of approximately 200- miles.

This would make it possible to use. two of the four courses and at thesame'time to reduce the angular width of the equisignal zone since the i two courses were displaced 180. .This is accomplished'by increasing the angle between the two primary coilsof the goniometer to about 120 instead of 90. Some installations of this type, were made. along the Transcontinental ,Airway.

I "Placing radio range-beacons in this manner course is usually broadest where it should be narrowest. To make this statement clear, it should .true angular function; that"is, directly; over the center of the loop antenna the courses have an infinitesimal Width, and gradually the width increases to approximately 6 miles at 100 miles dis- 'tance from the radio range. When a pilot flies 0 from a point atfa distance from the radio range sharper and narrower as he approaches the beacon installation, and if he keeps on his course it will take him directly over the radio tow'er. This feature alone is one of paramount importance and can not be neglected, since experience has shown that when the radio range is located adjacent to the terminal airport pilots are able to locate the airport and make safe landings when conditions are such that they would otherwise be unable to find the terminal airport. Hence, when a radio beacon is located at a terminal airport there are two very distinct advantages: First, the course becomes narrower as the pilot approached the beacon; second, the beacon informs the pilot one particularly annoying feature .in that the it is evident that his course gradually becomes definitely when he has passed' over the tower.

Therefore, itpractically fixes a point in space directly over the antennas. It is apparent that such a point in space would be of unquestionable value if locatedadjacent to a terminal airport instead of halfway between two airports. It waswith these particular features in mind that the problem of fitting radio ranges to the airways was attacked. I f p H The main object of my present invention, therefore, is the provision of a radiobeacon system whereby radiobeacon courses can be shifted by the addition of circular radiation intime-phase -withv the normal figure-of-eight radiation from the loop antennas.

Another object of my invention is the provision of a vertical antenna, locatedat the intersection of the two loop antennas and in inductive relation withthe radio transmitter so that its radiationis'in time phase with the radiation from the phantom antennas.

Another object of my invention is the provision of a vertical antenna, at the intersection of the two loop antennas, in inductive relation withone of the primary coils ofthe goniometer, and radiating in time phase with the phantom antenna of the said primary.

' Other objects as well as advantages of my system will be self-evident from the following description of my invention taken in connection with the accompanying drawings in which:

-Figure l is a schematic diagram of a radiobea- 'con system embodying my invention; first be understood that an equisign'al course is a Figure 2 is a schematic diagram of a radiobeacon system embodying a modification of my invention shown in Figure 1;

Figure 3 is a diagram showing the normal radiated space pattern of two loop antennas when the primary coils of the goniorneters are at with respect to each other. I

Figure 4 is a diagram of a field intensity patitern obtained by permitting a vertical antenna,

inductively coupled to both primary coils of the ,goniometer, to radiate in time phase withthe radiation from the phantom loop antennas.

Figure 5 is a diagram of a field intensity pat tern, obtained by permitting a vertical antenna inductively coupled to one of the goniometer pri- V maries to radiate in time phase with the radia- (Figure, l) indicatesfa master oscillator which rents in equal proportions to the control Likewise, the power output of passes through primary coils under consideration is connected for supplying radio-frequency currids of the intermediate amplifiers 2 and 5 operating in a pushepull circuit and cross-nee. ralized. 7 and 8 denote radio-frequency chokes. The power outputofzpasses throughthe condenser'ii to the control grid of the power amplifier/i;

the condenser 6 to the control g rid of the power amplifier v'7. The power output of 4 and 7 is transferred to thetuned tank circuit, comprising the variable condenser 8 and the variable inductors 9, 10 and 11, from which it is transferred, through the medium of the inductive relation existing between the coils 10 and 12, to the untuned link circuit comprising the condensers 14' and 15, the coupling coils l2 and 13, the primary coils of the goniometer P1 and P2 and the relay,-

24. Some of the, power. is then transferred to the vertical antenna .18 by .means' of the inductive relation between 13 and 16. The numeral 17 denotes the antenna tuning'inductor. 'The remainder of the poweris then transferred to the -loop antennas A andB means of the inductive relations existing between the primary coils of thergoniometer P1 and P2 and the secondary .coils'S1 and 52,; respectively. 21 and 22 denote the tuning inductcrsa'nd capacitances, respectively-, of. theloop antennas A. and B. The power for operating. the relay 24, which connectsthe primary coils oithe goniorneter P1 and Pg-to the tank circuit alternately is-supplied bythe conductors 23.

The diagram shown in' Figure 2 is'identic'al to" Figure '1 with the. exception of. themethodfor itransferringspower tothe verticalantenna. -In Figure .2, .the coupling coil 16 of the vertical antenna 18 iscoupled inductively to the primary coil P1 of the goniometer and is energized only when the'goniomet er primary P1 is connected to. the link circuit, while in Figural the vertical antenna is energized regardless of whether P1 orPzis in circuit. Ti 7 f The principle .of operation of my invention is best understood loy referring to the acc rnpanying radiated spacepatterns. Figure 3 is the radiatedspace pattern .of a typical. radio range when the goniom'eter primary coils .are set at 90 with respect toeach other (i. e., the space patterns obtained withthe circuits shownin'Figuresl and 2 when the vertical antenna is disconnected).

G and H" denote the figure-of-eight radiated space patterns of the two phantom loop antennas.

Eachprimary winding of the goniometer, acting in conjunction with the crossed secondarycoils and the two crossed-loop antennas, sets upa system (aphantomflloop antenna) which iselectrically equivalent to a single loop antenna The plane of this phantom antenna is dependent upon the relative coupling of the secondary coils to the Since there are two primary windings, two such phantom antennas exist, theangle between their planes beingequal to the an le. hetween'the pri-'.

mary windings or" the goniometer. Theftwo phantom antennas may be rotated in space (thus changing the position of the equisignal zones or courses formed by their space-patterns) by changing the relative position of the primary windings 'with respect to-the secondaries; This may be accomplished by rotating either the primary or the secondary coils. The four equisignal courses indicated by the cross-hatched areas L, M,- Nand P maintain fixed angles of'90 to each other when the goniometer primaries remain fixed at 90. It is understood that the goniometer secondary coils are always maintained at 90.

The preferred system shown in Figure 1, including thevertical antenna by means of which circular radiation is added in time phase to the normal figure-of-eight radiation from the phantom antenna's yields the radiation space pattern ShOWIIil'l Figure 4} It will be noted that one lobe of each of thenormal figure-of-eight patterns G and H is increased and the other decreased correspondingly, producing a shift of two of the courses MO and P0, in the direction of the smaller lobes. The amount of this shift may be controlled icy-adjusting the magnitude of the current in the vertical wire. This shift islirnited only by the disappearance of the two smaller 'The'amount of shift attainable with either arrangement (Figures 101' 2) depends, within certain limits, "upon the magnitude of the circular radiation and the power output of the transmitters and their ratiowith respect'to each other.

In. practical tests of this system conducted at B'ellefonte, Pennsylvania, excellent control or" the amount of shift was obtained by insertinga coupling coil in the common goniorneter primary circuitand coupling thereto the vertical antennainstalled on the radio range tower. Displacements as'large as 30 were readily obtainable.

The embodiment of the invention illustrated purpose of clearly setting forth the principles involved. It. will be. apparent, however, that the invention is'susceptible of being modified to meet the different conditions encountered .in its ion its

and described herein has been selected'for the use, and ,I,,.therefore, aim to cover by the ap pended claims all modifications within the true spirit and scope of my invention. 1

'What' I claim is: I .7

1. A 11161711011 01 shifting two radio beacon courses from their normal 180 degrees displace- J ment to align them with two airways intersecting at.a radiobea'con' at an angle other than 180 degrees .which consists in introducing circular radiation into the normal figure-of-eight radiations from the beacon.

h 2. A method ofchanging the angular displacement between two, of a plurality of equisignal courses from a radio beacon which consists in introducing circular radiation into the. normal figure-of-eight radiations from the beacon.

FRANK G. KEAB. 

